The present invention relates to stable dispersions of polyureas and/or polyhydrazodicarbonamides in a hydroxyl group-containing material.
Stable dispersions for use in manufacturing polyurethanes are known in the art. One particular family of such dispersions which has met with substantial commercial success are those polyureas and/or polyhydrazodicarbonamide dispersions prepared by reacting an organic polyisocyanate with (a) polyamines containing primary and/or secondary amine groups, and/or (b) hydrazines, and/or (c) hydrazides, in the presence of hydroxyl group-containing materials. See, e.g. U.S. Pat. Nos. 4,042,537 and 4,089,835. Other patents describing this type of dispersion include U.S. Pat. Nos. 3,325,421, 4,092,275, 4,093,569, 4,119,613, 4,147,680, 4,184,990, 4,293,470, 4,296,213, 4,305,857, 4,305,858, 4,310,448, 4,310,449, 4,324,716, 4,374,209, 4,496,678, and 4,523,025. While the commercially available dispersions are used to produce polyurethane products having excellent physical properties, it would be desirable if even further improvements could be realized.
The present invention is therefore directed to a novel process for producing stable dispersions, the dispersions so-produced, and their use in the manufacture of polyurethane products. These dispersions are characterized by solids of significantly smaller particle size. Foams produced from these dispersions exhibit improved load bearing properties.